landmann

SKA Statistics - Different methods for different architectures

Discussion created by landmann on Jan 22, 2011
Latest reply on Feb 2, 2011 by himanshu.gautam

The following picture of a simple stockham radix-2 made me think about what is going on in the SKA...

After compilation, the kernel's loops are unrolled for all architectures (I used constants in an #ifdef SKA - #endif block just for this purpose).

The numbers I get for the 4xxx series are more or less sane, but all numbers for the 5xxx series completely depend on the settings for avg. loop count. I could understand this in case the compiler was unable to unroll loops, but this happened. So why do these settings have any influence at all?

I think it is important to get proper feedback from these tools, otherwise they are quite useless. Atm I would rather measure the performance than using SKA if I had some more HW around :/

Same kernel, all loops known at compile time (unrolled asm)

 

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